Wireless devices connect to wireless networks in multiple and varied frequency bands by means of antenna(s). An antenna is a medium for transmitting and receiving electromagnetic waves. Antennas for portable wireless devices such as mobile telephones may be tuned to a variety of frequencies. Currently low bands fall in the range between 698 MHz and 960 MHz and mid/high bands fall into a range between 1427 MHz and 5 GHz such as for example, 2G GSM bands (850/900/1800/1900 MHz), 3G UMTS bands 5/2/1 (850/1900/2100 MHz), Bluetooth and Wi-Fi (2.4/5 GHz) and 4GLTE bands 17/5/4/2/1/7 (700/850/1700/1900/2100/2700 MHz). Antenna volumes are decreasing as larger displays are gaining popularity.
Such antennas have evolved to address two competing interests: provide access to ever-increasing numbers of communication protocols using a multitude of frequency bands, and provide such an antenna in an ever-decreasing form factor. Perimeter ring antennas have emerged to address these competing interests. A typical ring antenna includes an external portion around an outer edge of a mobile device. Gaps may be provided in the ring to in part control the frequencies to which the antenna is tuned and counteract hand loading while being used.
Conventional ring antennas suffer from certain industrial design drawbacks. First, the full-thickness ring (i.e., full thickness of the mobile device) takes up space which could advantageously be used for other ports or components. Second, the performance of conventional full-thickness rings significantly degrade when held in a hand or against a head due to absorption of radiation by the hand or head. Third, there is a need to maximize the number of antenna in mobile devices to service additional frequency bands than are not currently serviceable with conventional ring antennas.